1. Technical Field
The present disclosure relates generally to the administration of fluids to a body, particularly to medication infusion systems for subcutaneous injection/aspiration. More specifically, the present disclosure is directed to handpieces for such medication infusion systems that facilitate operability over a range of pressure for infusing medication safely and painlessly during a medical and/or dental procedure.
2. Description of the Related Art
Infusion pump devices and related systems are well known in the medical arts for use in the administration of medication to a patient. The administration of medication has been described in the art as administration to a patient through infusion tubing and an associated catheter, needle cannula, or the like, to introduce the medication intravenously. Some of these systems can determine infusion line occlusion. Line occlusions may cause the pressure in a syringe of the system to increase. Various systems are available to identify a predetermined threshold or to monitor pressure to determine selected ranges of occlusion pressures to insure patient safety. See, for example, U.S. Pat. Nos. 5,295,967; 4,731,058; and 5,080,653, which disclose systems (with syringe pumps or the like) intended for use of intravenous drug delivery and more specifically for monitoring occlusion during infusion. However, these systems do not provide drug delivery or aspiration subcutaneously via a hypodermic needle.
Accurately positioning a hollow-bore needle within tissues to deliver medication within tissue structures has long been a challenge in both medicine and dentistry. The inability to accurately position a hollow-bore needle within specific tissues (e.g., soft-tissues) or organs can lead to a failed medical objective. Locating pathologic tissue types (e.g., neoplasia, tumors, cysts and the like) is relevant to aspiration of these tissues as well as the infusion of therapeutic medications to treat these local lesions of the body. Hence, locating a specific anatomical site has been previously assisted by using ionizing radiation, ultrasound, MRI, electrical-stimulators and other invasive diagnostic devices that require secondary techniques to be employed to assist the practitioner in determining the accuracy of the placement of a needle within tissue.
Pain, tissue damage and post-op complications have long been tolerated as negative side effects from the use of existing hypodermic medication delivery injection systems. The pain and tissue damage are a result of uncontrolled flow rate in conjunction with excessive pressures created during the administration of medication solutions within the tissue spaces. Subjective pain response of a patient has been demonstrated to be minimized at specific flow rates during the administration of a medication. Also, it is known that particular pressures, such as those that are excessive without occlusion, for a specific tissue type can cause damage.
Various devices have been disclosed in an attempt to overcome the above referenced complications and related issues. See, for example, U.S. Pat. Nos. 4,747,824; 5,180,371. These devices typically include a handpiece for administering medication from a vial, cartridge, etc. to a patient. The handpiece assembly may include various components such as, for example, conduits, needle assembly, cartridge holder, etc. These handpiece assemblies can suffer from a variety of drawbacks and disadvantages. For example, many of these disposable handpiece assemblies are not suitable for a specific high pressure range. Under high pressure conditions the components of the handpiece assembly are susceptible to distortion, deformation of shape, fracture and leakage resulting in failure to achieve the desired clinical effect.
Further, handpieces that require a practitioner to affix a needle of the assembly suffer from the risk of improper installation, which may result in leakage during use. Improper connection of tubing of the handpiece assembly, such as connection to a cartridge carrier, can lead to leakage at the corresponding interface, particularly at high pressures. Practitioner assembly can also result in an inadequate tightening and sealing of components. Minor variations in manufacturing tolerances of components of the handpiece assembly, in particular needle hubs may result in discrepancies between components such that upon assembly, leakage may occur.
Moreover, microbore tubing used with such handpiece assemblies can deform under pressure resulting in an internal ballooning. This ballooning of tubing results in ineffective infusion/aspiration as solution becomes retained within tubing thereby preventing administration of fluid. In particular, microbore tubing is susceptible to distortion under specific pressures. This specific pressure range can lead to deformation of tubing in which tubing absorbs the medication solution within the physical length of tubing resulting in ballooning of the micro-tubing. When this occurs the solution is retained within the micro-tubing and does not reach the intended tissue site, disadvantageously leading to failure.
Therefore, it would be desirable to overcome the disadvantages and drawbacks of the prior art with a handpiece for a medication infusion system that facilitates operability over a range of pressure for infusing medication safely and painlessly during a medical and/or dental procedure. Desirably, the handpiece of the medication infusion system is a disposable handpiece assembly including a needle, tubing and cartridge holder, which utilize a sealing bond to ensure a lack of fluid leakage or distortion of the system components for a specified range of pressures. Most desirably, the handpiece assembly of the medication infusion system is configured for operability in a range of 200 pounds per square inch (psi) to 650 psi, to achieve the principles of the present disclosure. It is contemplated that the handpiece assembly of the medication infusion system and its constituent parts are easily and efficiently manufactured and assembled.